A spondee is a foot composed of . two accented syllables
two unaccented syllables
an unaccented syllable followed by an accented syllable
an accented syllable followed by an unaccented syllable

A spondee is a foot composed of two accented syllables.

Explanation:

In poetry, we speak of meter when we refer to the rhythmic structure of the lines. Each line will have a number of syllables, and those syllables may be stressed or unstressed, which creates the rhythmic pattern.

A foot is the basic unit of a meter. There are several kinds of metrical feet, one of them being called spondee. A spondee consists of two stressed or accented syllables. A common example given to clarify spondee is "bus stop", which has two stressed syllables. Other types of feet are, for instance, an anapest (two unstressed syllables followed by a stressed one), an iamb (one unstressed syllable followed by a stressed one), and a dactyl (one stressed syllable followed by two unstressed ones).

mark twain, real name samuel langhorne clemens, was an american writer, humorist, entrepreneur, publisher, and lecturer. among his novels are the adventures of tom sawyer and its sequel, the adventures of huckleberry finn, the latter often called "the great american novel". wikipedia

●intensive purposes is the correct answer